PHYSICAL FACTORS INFLUENCING THE COMPLETENESS OF REMOVAL OF RESIDUAL PERFLUOROCARBON LIQUID IN VITREORETINAL SURGERY.

Abstract

Postoperative perfluorocarbon liquid (PFCL) retention would lead to serious complications, especially retinal toxicity and intraocular inflammation. This study aimed to elucidate the roles of air infusion pressure and residual balanced salt solution in PFCL evaporation during vitreoretinal surgery, thereby optimizing residual PFCL removal, minimizing complications, and improving patient outcomes. Evaporation rates of perfluoro-n-octane and perfluoro-decalin were studied using a 3D-printed eye model under varying air infusion pressures from 10 to 40 mmHg. Computational fluid dynamics simulations were used to qualitatively capture PFCL evaporation dynamics, followed by interpretation with a quantitative mathematical model, which also elucidates the impact of the balanced salt solution film on PFCL evaporation. In the 3D-printed eye model, PFCL completely evaporated at rates of 1.03 µ L/second (perfluoro-n-octane) and 0.28 µ L/second (perfluoro-decalin) at an air pressure of 30 mmHg. Perfluorocarbon liquid evaporation rate increased almost linearly from 10 to 30 mmHg ( P < 0 . 05 ) before reaching its maximum level. Computational fluid dynamics simulations revealed enhanced PFCL evaporation rate as air pressure rises. A mathematical model, based on inlet air pressure enhanced PFCL vapor diffusion, was derived to quantitatively capture PFCL evaporation under clinical conditions with balanced salt solution. Both in vitro experiments and mathematical models indicate that trace amounts of PFCL could evaporate completely under surgically representative air pressure levels without significantly extending surgical time. Inlet air pressure significantly accelerates PFCL vapor diffusion rate, dominating PFCL evaporation. The height of the balanced salt solution film exerts a determinant effect on the evaporation of PFCL even under the surgically relevant air infusion pressure level.